Bioactive component in guggulu, q.v., the gum resin of the Ayurvedic medicinal plant, Commiphora mukul, Burseraceae, used in treatment of lipid disorders. Both the E- and Z- isomers are naturally occurring and bioactive. Synthesis and stereochemistry: W. R. Benn, R. M. Dodson, J. Org. Chem. 29, 1142 (1964). Isoln from guggulu: V. D. Patil et al., Tetrahedron 28, 2341 (1972). HPLC determn of isomers in serum: N. Verma et al., J. Chromatogr. B 708, 243 (1998). LC determn of isomers in commercial guggulu formulations: M. Nagarajan et al., J. AOAC Int. 84, 24 (2001). Inhibition of the bile acid receptor FXR and cholesterol lowering activity: N. L. Urizar et al., Science 296, 1703 (2002). Brief review of proposed mechanism of action: C. J. Sinal, F. J. Gonzalez, Trends Endocrinol. Metab. 13, 275-276 (2002).